"The Amazon has often been described as the world's lungs. Its protection matters to the whole international community," they said.

"We call on the Morrison government to do everything they can to encourage Brazil to respond to this rapidly worsening global disaster."

They said failure to defend against or prevent these fires stands to derail any international efforts against climate change.

The US Trump administration said it was "deeply concerned" about the wildfires, which now look set to be discussed at a summit of G7 leaders in France this weekend and where Australian Prime Minister Scott Morrison is a guest.

Liberal senator Paul Scarr said what is happening in the Amazon is a great concern having seen the footage of the illegal burn off.

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"There is an 84 per cent increase in the burn off on the Amazon year-on--year from last year ... so that''s a great concern for the world," Senator Scarr told ABC television on Saturday.

"I'm sure that's going to be a major topic of discussion at the G7 meeting."

European leaders have already threatened to tear up a trade deal with South America, reflecting the growing international dismay and anger with Brazil.

Against the global chorus of condemnation, Brazilian President Jair Bolsonaro said he is mobilising the army to help combat the blazes, while his administration launched a diplomatic charm offensive to try to mend bridges.